Semiconductor image pickup devices such as CMOS image sensors are increasingly miniaturized and generally use copper (Cu) wires. When copper wires are used, a cap layer such as a silicon nitride film needs to be provided on the copper wire in order to prevent diffusion of the copper.
However, in a pixel area, a part of the cap layer which is located over a photoelectric conversion element is removed in order to suppress attenuation of light incident on the photoelectric conversion element. On the other hand, non-pixel areas such as a dummy pixel area and a black reference area do not require suppression of light attenuation. Thus, in these areas, the cap layer is not removed. Hence, during a sinter process, the amount of hydrogen supplied to a substrate differs between the pixel area and the non-pixel area. As a result, disadvantageously, a dark characteristic and the like may vary between the pixel area and the non-pixel area.
As described above, characteristic differences may conventionally occur between the pixel area and the non-pixel area, making production of excellent semiconductor image pickup devices difficult.